Variable tensioner

Abstract

A variable tensioner according to an exemplary embodiment of the present invention may include: a base, an arm including a boss and a mounting portion, wherein the boss is co-axially and rotatably coupled to the base and a pulley is coaxially and rotatably mounted to the mounting portion, the arm forming an elastic member insert recess with the base, an elastic member mounted in the elastic member insert recess, one end of the elastic member fixed to the base and the other end of the elastic member fixed to the boss, and a tension actuator deforming a portion of the elastic member according to signal of an engine control unit.

1 . A variable tensioner comprising:
 a base;   an arm including a boss and a mounting portion, wherein the boss is co-axially and rotatably coupled to the base and a pulley is coaxially and rotatably mounted to the mounting portion, the arm forming an elastic member insert recess with the base;   an elastic member mounted in the elastic member insert recess, one end of the elastic member fixed to the base and the other end of the elastic member fixed to the boss; and   a tension actuator deforming a portion of the elastic member according to signal of an engine control unit.   
   
   
       2 . The variable tensioner of  claim 1 , wherein the elastic member insert recess is enclosed by the base and the boss. 
   
   
       3 . The variable tensioner of  claim 1 , wherein the boss and the mounting portion of the arm is integrally formed of a single body. 
   
   
       4 . The variable tensioner of  claim 3 , wherein the base and the boss are coupled by a first connecting member, the base is fixed so that the boss is rotatable relative to the base, and the mounting portion and the pulley are coupled by a second connecting member. 
   
   
       5 . The variable tensioner of  claim 4 , wherein the first connecting member and the second connecting member is offset with a predetermined distance. 
   
   
       6 . The variable tensioner of  claim 5 , wherein the first connecting member is a shaft. 
   
   
       7 . The variable tensioner of  claim 5 , wherein the second connecting member is a bolt. 
   
   
       8 . The variable tensioner of  claim 4 , wherein the elastic member is wound substantially around the first connecting member. 
   
   
       9 . The variable tensioner of  claim 3 , wherein the base comprises an interior circumference, an exterior circumference, and a protruding portion configured to be disposed between the interior circumference and exterior circumference thereof, and the boss comprises an interior circumference and an exterior circumference wherein the exterior circumference of the boss protrudes downwardly and contacts the exterior circumference of the base and the interior circumference of the boss protrudes downwardly and a lower portion of the interior circumference of the boss is slidably inserted in a boss insert groove of the base formed between the interior circumference and protruding portion of the base. 
   
   
       10 . The variable tensioner of  claim 9 , wherein the elastic member insert recess is disposed between the interior circumference and exterior circumference of the base and the interior circumference and exterior circumference of the boss. 
   
   
       11 . The variable tensioner of  claim 10 , wherein the elastic member is wound substantially around the interior circumference of the base and the interior circumference of the boss in the elastic member insert recess. 
   
   
       12 . The variable tensioner of  claim 1 , wherein the tension actuator is provided with one end fixed to the base and the other end disposed in close proximity to a portion of the elastic member. 
   
   
       13 . The variable tensioner of  claim 12 , wherein the tension actuator rotationally deforms the portion of the elastic member so as to enforce torsion moment when the tension actuator is activated. 
   
   
       14 . The variable tensioner of  claim 13 , wherein the tension actuator is a piezoelectric element. 
   
   
       15 . The variable tensioner of  claim 1 , wherein the engine control unit controls the tension actuator in a case that the engine speed is less than or equal to a predetermined speed so as to extend the tension actuator. 
   
   
       16 . The variable tensioner of  claim 15 , further comprises a crank shaft position sensor detecting the phase angle of a crankshaft and sending the detected phase angle to the engine control unit to calculate the engine speed. 
   
   
       17 . The variable tensioner of  claim 16 , wherein the predetermined engine speed is 2000 RPM.